Patent DE-102013201463-A1 (DE)
Title: Apparatus, useful for welding a welding element to workpiece, comprises pressure-generating device, and changeover device that is designed such that the pressure is changed by operation of changeover device using additional spring element
Inventor: KNAPPE PETER
IPC: B23K9/20
Filed: 2013-01-30
Abstract: The welding apparatus comprises a housing (1), a welding element holder (8) for holding a welding element (7), a pressure-generating device for generating a pressure on the holder along an axis (A), and a changeover device (4). The generating device comprises a spring element and an additional spring element. The changeover device is designed such that the pressure is changed by the operation of the changeover device using the additional spring element. The apparatus is designed such that the welding device is changed from a first mode to a second mode by the operation of the changeover unit. The welding apparatus comprises a housing (1), a welding element holder (8) for holding a welding element (7), a pressure-generating device for generating a pressure on the welding element holder along an axis (A), and a changeover device (4). The pressure generating device comprises a spring element and an additional spring element. The changeover device is designed such that the pressure is changed by the operation of the changeover device using the additional spring element. The welding apparatus is designed such that the welding device is changed from a first mode in which it is suitable for a gap welding, to a second mode in which it is suitable for contact welding, by the operation of the changeover unit, and is changed from the second mode to the first mode by the further operation of the changeover device. The changeover device is moved from a first position to a second position with respect to the housing, and is mechanically secured in the first position and/or in the second position. The operation of the changeover device is carried out manually and/or by a control signal. The spring element is provided by a spring constant, and the additional spring element is provided by an additional spring constant. The spring constant and the additional spring constant are different. The spring constant of the additional spring element is 10% larger than the spring constant of the spring element. The spring element is formed by a compression spring, and/or the additional spring element is formed by an additional compression spring. The spring element and the additional spring element are arranged one behind the other with respect to the axis, or are overlapping and interlocking with each other. The changeover device varies the pressure of a stop element for the additional spring element, and is designed such that the stop element is moved parallel to the axis with respect to the housing by a distance of 5-30 mm using the operation of the changeover device. The operation of the changeover unit is carried out with respect to the housing. The changeover device is moved parallel to the axis and/or rotated around the axis. The apparatus further comprises an electromagnet for an electromagnetic pick-off of the welding element on a surface portion of the workpiece, and a fine setting device for fine adjustment of pressure. A magnetic circuit of the electromagnet is interrupted during the operation of the changeover device. The welding apparatus is designed such that a measure of the lifting-off distance is changed.